Method and system for dual mode access for storage devices

• US 20070033373A1
• Filed: 08/03/2005
• Published: 02/08/2007
• Est. Priority Date: 08/03/2005
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Corporation (Western Digital Corporation)
• Inventors: Sinclair, Alan
• Granted Patent: US 7,627,733 B2
• Time in Patent Office: Days
• US Class Current: 711/203
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing

Abstract

A method and system for reading data from a non-volatile mass storage device is provided. The method includes, performing logical configuration for the non-volatile mass storage device, wherein file data is allocated addresses in a virtual logical address space; and data identified by virtual logical addresses is read by a host system. The system includes a file storage segment that reads and writes data on a file-by-file basis, allowing a host system to access data from the non-volatile mass storage device using a file interface format; and a logical interface segment that allows the host system to access data using logical addressing, wherein the host system is unaware of a storage format under which data is stored on a file-by-file basis.

Claims

1. A method for reading data from a non-volatile mass storage device, comprising:

performing logical configuration for the non-volatile mass storage device that stores file data on a file-by-file basis, wherein during the logical configuration a logical index is created where the logical index includes an entry for each file that is identified in a file directory and each entry specifies an address for a file within a virtual logical address space for the non-volatile mass storage device and a corresponding entry location in the file directory; and

operating the non-volatile mass storage device wherein data identified by the virtual logical address is read by the host system.

2. The method of claim 1, wherein during a logical read-only mode, entries relating to a logical sector address from the host system is converted to an entry address in the file directory with a file offset address obtained from the entries in the logical index.

3. The method of claim 2, wherein sector data is read via a direct data file storage manager.

4. The method of claim 1, wherein during the logical configuration, a file allocation table (“

FAT”

) index is created which includes a list for each FAT sector and provides an entry number for each FAT sector number.

5. The method of claim 4, wherein during the logical read only mode, entries relating to a FAT sector are updated based on entries in the FAT index, before being sent to the host system.

6. The method of claim 1, wherein the host system is unaware of a storage format which allows data to be stored on a file-by-file basis by the non-volatile mass storage device.

7. A system for reading data in a non-volatile mass storage device, comprising:

a direct data file storage segment that operates in a direct data file access mode allowing a host system to access data from the non-volatile mass storage device on a file-by-file basis; and

a logical interface segment that allows the host system to access data using logical addressing, wherein the host system is unaware of a storage format under which data is stored on file-by-file basis.

8. The system of claim 7, wherein the logical interface includes a directory index, a file allocation table (“

FAT”

) index and a logical index created during a logical configuration mode.

9. The system of claim 8, wherein in the directory index a virtual logical address is assigned to each entry in a file directory.

10. The system of claim 8, wherein the logical index includes an entry for each file that is identified in a file directory and each entry specifies a virtual logical address space and a corresponding entry location in the file directory.

11. The system of claim 8, wherein the FAT index includes a list for each FAT sector and provides an entry number for each FAT sector number.

12. The system of claim 8, wherein during a logical read-only mode, entries relating to a directory sector are read from a file directory and modified by an entry from the directory index.

13. The system of claim 8, wherein during a logical read-only mode, entries relating to a logical sector address from the host system is converted to an entry address in a file directory with a file offset address obtained from entries in the logical index.

14. The system of claim 8, wherein during a logical read only mode, entries relating to a FAT sector are updated based on entries in the FAT index, before being sent to the host system.

15. A method for reading data from a non-volatile mass storage device that stores data on a file-by-file basis, comprising:

performing logical configuration for the non-volatile mass storage device, wherein file data is allocated addresses in a virtual logical address space; and

data identified by virtual logical addresses is read by a host system.

16. The method of claim 15, wherein during a logical read-only mode, entries relating to a logical sector address from the host system is converted to an entry address in a file directory with a file offset address obtained from entries in a logical index table.

17. The method of claim 16, wherein sector data is read via a direct data file storage manager.

18. The method of claim 15, wherein during a logical configuration, a file allocation table (“

FAT”

) index is created which includes a list for each FAT sector and provides an entry number for each FAT sector number.

19. The method of claim 18, wherein during a logical read-only mode, entries relating to a FAT sector are updated based on entries in the FAT index, before being sent to the host system.

20. The method of claim 15, wherein the host system is unaware of a storage format under which data is stored on a file-by-file basis by the non-volatile storage device.

21. A system for reading data from a non-volatile mass storage device, comprising:

a file storage segment that reads and writes data on a file-by-file basis, allowing a host system to access data from the non-volatile mass storage device using a file based protocol; and

a logical interface segment that allows the host system to access data using logical addressing, wherein the host system is unaware of a storage format under which data is stored on a file-by-file basis.

22. The system of claim 21, wherein the logical interface segment includes a directory index, a file allocation table (“

FAT”

) index and a logical index created during a logical configuration mode.

23. The system of claim 22, wherein in the directory index, a virtual logical address is assigned to each entry in a file directory.

24. The system of claim 22, wherein the logical index includes an entry for each file that is identified in a file directory and each entry specifies a virtual logical address space and a corresponding entry location in the file directory.

25. The system of claim 22, wherein the FAT index includes a list for each FAT sector and provides an entry number for each FAT sector number.

26. The system of claim 22, wherein entries relating to a directory sector are read from a file directory and modified by an entry from the directory index.

27. The system of claim 22, wherein entries relating to a logical sector address from the host system is converted to an entry address in a file directory with a file offset address obtained from entries in the logical index.

28. The system of claim 22, wherein entries relating to a FAT sector are updated based on entries in the FAT index, before being sent to the host system.